When will my sweat joints leak?

Discussion in 'Plumbing Forum, Professional & DIY Advice' started by jok, Jan 29, 2012.

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  1. Hackney plumbing

    Hackney plumbing Homeowner

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    250 psi is childs play......I'm talking thousands of pounds. The caps have already been tested with 400 psi for 6 hours without any problem. I used a rex wheeler hydro test pump. I also tested a 3/4 sharkbite slipped onto 1/2" galvanize pipe......that test lasted 6 months on the bench before I disassembled it........it helld 400 psi.

    I'm going to test them with hydraulic fluid until the pipe or joint literally fails and splits open. I believe his rig can go near a 100,000 psi......so thats more than enough for a copper pipe test. LOL

    Yeah I know it wasn't alot of solder.....its a 1/2" joint. Notice it didn't drip.......what hits the floor doesn't help. It was 95/5 lead free solder.

    I need to have a guy with a propress press me a cap on so i can test it to failure.........I'm not a huge fan of propress but I'm not against it either.

    Whats funny Terry is that I've been plumbing for close to 30 years and I have a large customer base that I have kept........you dont have that kind of business doing crappy work and having leaks. I haven't had a leaking joint in so many years I cant remember the last one I had.

    Steam expands ALOT more than air.......sediment/scale in the pipe holds moisture and that moisture is converted to steam as you heat the pipe.

    CORRECTION: I just got off the phone with my friend and he said he can test it to about 65,000 psi with his current rig.........I'll probably be going to get it tested tomorrow. Depends on my work load......and as we service plumbers know you can get more than you can handle with one phone call.
     
    Last edited: Feb 1, 2012
  2. Hackney plumbing

    Hackney plumbing Homeowner

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    Burst pressure for 1/2" soft copper is 3,885 psi. Anyone know what the 95/5 solder joint would be rated at for failure?

    Hope you guys are having as much fun as I!!! I love testing crap.....

    Add: My friend just called me back that has the test equipment,he wants me to call him beofre I go to have it tested.....he says he has never blown any copper and wants to be there when its tested.

    So its for sure on now......first chance I get that both of us can be there.
     
    Last edited: Feb 1, 2012
  3. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

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    How loose the fitting is, how long you heat it (DIY'ers tend to overheat things), the type and quantity of flux used, and how much air there is in the pipe itself to expand will all add complications to determining if any single joint will fail. It IS a possibility. What might be as interesting would be to do that soldering on a closed system, multiple joints so the whole thing gets hot, and have one of them going to an air pressure gauge you've got plumbed into the mess. A fitting pushed over type K copper verses one on type M might make a difference as well - one would be a lot tighter than the other before soldering. The basic physics is dictated by the universal gas law I quoted...there's a reason why it's called a universal gas law - it applies to our whole known universe - you aren't exempt! Heated gasses in a closed volume will try to expand, thus increasing pressure. State changes of a liquid to gas expand even more, but even once it is a gas, it still expands as you heat it, or increases pressure if it can't expand.
     
  4. Hackney plumbing

    Hackney plumbing Homeowner

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    Sure the air expands. I never said it didn't...did I?

    What I did say is that the joint is not air tight as you heat it. Once the pipe and fitting are up to temp......all the expanding has already taken place. You apply the solder and let it cool.

    Are you telling me that the air in the pipe continues to expand once it hits the target temp? I agree if you overheat the fitting and pipe your asking for multiple problems to start happening.
     
  5. Hardt

    Hardt Member

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    Location:
    Hawaii
    Interesting how this thread developed into the question of integrity of a sweated joint in a closed system! Here is my 2 cents worth... I ran into this problem not with plumbing but with the gas tank float in my "93 Ford Explorer. After my suv was about 7 years old the gas gauge gave a false low reading because the float, a brass cylinder, about 1" x 2 1/2", comprised of the two ends sweated in the middle to make one and a sweated closed pin hole in one end, filled with gas. I am not an experienced sweater-of-joints in plumbing but being in electronics my entire life, I have soldered probably thousands of electrical connections. I re-sweated the seams and re-installed same. Three months later the problem returned! My friend gave me another used float and I re-sweated it , installed it and it failed in a few months! I went back to the original float, re-sweated it, and thought I would give it a test before re-installing. I put it in my garden sprayer filled with water, weighted the float so it would be submerged and pumped the heck into the sprayer. After 24 hours, I took it out and it had not leaked... problem solved! Put it into my gas tank and it failed within 3 months!!:mad: I bought a new float and it has been holding out now for about 10 years. :eek: I don't know if it was the pressure when I sweated the seams that compromised the seal or the vacuum after it cooled down but I'll never again try to do this type of repair again!!!
     
  6. Hackney plumbing

    Hackney plumbing Homeowner

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    OK I completed another test. I connected a gauge to the pipe and soldered a cap on. It has a reading of ounces per sq in. OUNCES. The needle did not move at all until after I applied the solder.....it developed 1.5 tenths of an OUNCE of pressure then immediately went back to zero.

    The joint is perfect. I'm going to test to to failure...no matter what PSI it takes to make it pop.

    I let the pipe totally cool down.......then heated it with my torch. After a few seconds the needle takes off like a rocket. I didn't want to damage my gauge so I stopped.

    http://www.youtube.com/watch?v=9vjczsdok2s

    http://www.youtube.com/watch?v=mMnhNYZD0D4
     
    Last edited: Feb 1, 2012
  7. bluebinky

    bluebinky Member

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    This is what I was curious to see... I'd wager that the joint will hold up well. However, if you took a joint I did it might not do as well.

    So ... my conclusion is that if you know you have perfect technique every time then don't worry about it. If you're not so perfect or just plain careful, then open a valve!
     
  8. Hackney plumbing

    Hackney plumbing Homeowner

    Joined:
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    To be honest I dont think its technique. The biggest part to soldering happens before you solder.......you must get the moisture out of the pipe or make a way for it to relieve itself. If you convert to steam its going to blow your joint out unless you have the pipe open to atmospheric pressure...that means removing alot of water.

    There is a way to avoid this. First you get all the water you can out of the pipe by opening faucets and letting it drain. If you can apply a bit of downward pressure to allow the pipe to drain. Close all the faucets.....yes close them. Its like holding your finger over a straw full of water...it has no air and cannot drain anymore. Thats what you want after the initial drain down. Now its time to remove the remaining water a few feet in each direction of the pipe your repaiiring. I use a pice of pex tube and run a few feet into the line if I can and blow....this blows alot of the water out. Once you have all the water blown out,you strike your torch up and heat several feet in each direction if you can....this dries the moisture out of the pipe so it doesn't flash to steam when your soldering. Water runs to heat.....so if you start to get a trickle when your pre-heating you know that you must go back and use the pex tube or another way to get the water out.

    When your preheating the pipe in each direction and your not getting water or steam.....its time to assemble the joint quickly and solder it.

    Leaving the faucets open could actually makes things worse......when your heating the joint,this will allow air to be sucked in and move water toward your joint.

    Notice in the last video that when I remove the flame from the pipe the gauge almost immediately stops. I like that.
     
    Last edited: Feb 1, 2012
  9. ballvalve

    ballvalve General Engineering Contractor

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    northfork, california
    Are we getting a pressure test on that double capped pipe?
     
  10. Hackney plumbing

    Hackney plumbing Homeowner

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    YES!!! As soon as I get time. I cut the pipe in half so I can test each end. I hope to get it done by the end of the week......the owner of the business wants to watch too. He says he nevr tested any copper tube but looks forward to making it fail.

    I'm also going to take some pex and see what it will hold before somthin happens....

    His test machine will pretty much make anything us plumbers use go POP. 65,000 PSI test pump.
     
  11. ballvalve

    ballvalve General Engineering Contractor

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    Location:
    northfork, california
    Lets remember that while this is all interesting, copper fails from water chemistry, not pressure issues.

    How about doing a 'copper' epoxy-on cap test?

    Or a 10 year old used piece of M copper?
     
  12. ahosh

    ahosh New Member

    Joined:
    Feb 9, 2012
    Location:
    Westchester, NY
    easier way?

    Perhaps there is an easier way? Maybe a balloon or something on one end of pipe, that will show a tiny pressure change, then soldering on a cap. I know a balloon would melt, but I'm sure there is a way to do this more easily to determine if hot air expands with no water present. Maybe a balloon on a beaker on a hot plate.

    Interesting thread.
     
  13. Hackney plumbing

    Hackney plumbing Homeowner

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    A balloon??? I was measuring inches of water column in the video......it barely even moved the gauge. I can exhale normally and peg the gauge out. A ballon wouldn't do anything but lay there in the test I did.

    Watch the videos.

    For the others interested in the thread...I'ma try very hard to get the pipes tested today. its friday and I'm sore from correcting other peoples mistakes in crawlspaces...LOL I dont wanna work today!!!!!!!!
     
  14. Hackney plumbing

    Hackney plumbing Homeowner

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    I think today might be the day to test the coppa. Cant say for sure but it looks like it. The test bench is 60 miles away but i will be in the area. Hopefully the owner will be available...otherwise i will have to pay for it. His employees are instructed to charge anyone no matter who they are,no exceptions. I dont blame him.....thats one reason why he's a multi-millionaire at 40 years old.

    I'm excited!!!!! LOL thats sick.

    Wow time flys by.....its late,I hafta get to work. Stay tuned folks......its about to get good.
     
    Last edited: Feb 15, 2012
  15. pipehacker

    pipehacker New Member

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    Location:
    Iowa
    Is there any way that you can do a test on a sharkbite?
     
  16. Hackney plumbing

    Hackney plumbing Homeowner

    Joined:
    Jan 6, 2010
    Location:
    Alabama
    [​IMG]

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    I did the test today on one piece of the copper. People wer waiting to have hoses made that are actually needing them.

    The copper FAILED but not at the joints.....anyone want to guess what the max pressure went to?
     
  17. Hackney plumbing

    Hackney plumbing Homeowner

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    Location:
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    Here is the deal. The type L soft copper tube swelled up and popped.

    The cap held fine. I will be testing more pieces and will take some pex and a sharkbite.

    [​IMG]

    [​IMG]

    [​IMG]
     
  18. Tom Sawyer

    Tom Sawyer In the Trades

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    Hey TM, where does a busy guy like you find the time to do this stuff?
     
  19. Hackney plumbing

    Hackney plumbing Homeowner

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    It seems you would be curious what pressure the pipe failed at.

    I like to spend my time doing somthing constructive rather than to worry about how another guy spends his time. Thats probably why I'm so successful. Some people like to drink beer,some people play video games,some people like to eat......I like to do plumbing experiments.

    It helps separate the B.S. from fact. Did you enjoy my fact presentation?
     
    Last edited: Feb 16, 2012
  20. ballvalve

    ballvalve General Engineering Contractor

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    "retired" and still building and troubleshooting
    Location:
    northfork, california
    Nice project. What was the PSI? I would guess lower than thought, under 1000. I want to see some OLD type m get pressurized. Actually I have a hydraulic Govt. surplus hand pump that puts out about 50,000 PSI. But I wish I had the time to screw with all the connections needed.

    I find it humorous that 3/8" 2500 PSI hydraulic hose in stock lengths costs about the same or less than those shiny flex supply lines with god knows what crap inside. First guy to line hydraulic line with pvc will make a fortune.

    Actually you could do it at home in the freezer if you can find a pressure gauge that doesnt use a water filled bourdon tube as the actuator. Get a kid to do it at the science fair. A very useful test would be to freeze various types of pipe and see which ones held together at about 10 to 15 below zero. I disconnect the thermostats on my freezers and they hold at about that. I can freeze a steak for 4 years and they still taste like new.

    I have two of these hand pumps - cost the govmt. about 4 grand each. Make an offer. You could build a quick rig with a hydraulic jack pushing on another hydraulic cylinder that connects to your pipes, do it in a arbor press.

    Test some flex supply lines for us. Actually, you could use a pressure washer for testing supply lines fairly easily, and save a 60 mile ride. Sell the data to consumer reports.
     
    Last edited: Feb 16, 2012
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